So to alleviate the device's requiring prohibitive amounts of energy to operate, it just needs to be made out of particles that haven't even been encountered.We've known that all along.
Dilithium Crystals 
As the key element in all Federation warp engine designs, the dilithium crystal mediates the reaction between the matter and anti-matter in a starship's main engine core.
Dilithium is the only material known to be non-reactive with antimatter when subjected to a high frequency electromagnetic (EM) field, rendering it "porous" to antihydrogen.
Dilithium permits antimatter to pass directly through it's crystalline structure without actually coming into contact with it, due to a field dynamo effect.
Once found only in nature, the technology of the 24th Century antieutectics enables the formation of pure, synthesized dilithium and dilithium matrix re-crystallization through the use of high energy photon injection.
